1000 - 47 . 72 - 47 .28

= 47 . ( 1000 - 72 -28 )

= 47 .0

=0

3457 - 27 . 48 - 48 .73 + 6543

=3457 - 48 . (27 + 73 ) + 6543

= 3457 - 4800 + 6543

= 5200

a) \(\left(145\times99+145\right)-\left(143\times102-143\right)\)

\(=\left[145\times\left(99+1\right)\right]-\left[143\times\left(102-1\right)\right]\)

\(=\left(145\times100\right)-\left(143\times101\right)\)

\(=14500-14443\)

\(=57\)

b) \(54\times47-47\times53-20-27\)

\(=47\times\left(54-53\right)-20-27\)

\(=47-20-27\)

\(=0\)

c) \(10000-47\times72-47\times28\)

\(=10000-47\times\left(72+28\right)\)

\(=10000-47\times100\)

\(=10000-4700\)

\(=5300\)

d) \(3457-27\times48-48\times73+6543\)

\(=\left(3457+6543\right)-48\times\left(27+73\right)\)

\(=10000-48\times100\)

\(=10000-4800\)

\(=5200\)

a) 27 x 35 + 73 x 6 - 27 x 29

= 27 x ( 35 - 29 ) + 73 x 6

= 27 x 6 + 73 x 6

= 6 x ( 27 + 73 )

= 6 x 100

= 600

b) 29 x ( 47 + 53 ) - 47 x ( 29 + 53 )

= 29 x 47 + 29 x 53 - 47 x 29 + 47 x 53

= 29 x ( 47 + 53 - 47 ) + 47 x 53

= 29 x 53 + 47 x 53

= 53 x ( 29 + 47 )

= 53 x 76

= 4028

c) 5 x 17 x 4 x 25 x 20

= ( 5 x 20 ) x ( 4 x 25 ) x 17

= 100 x 100 x 17

= 10000 x 17

= 170000

Mới lớp 3!

lớp 3 cút , ng ta nói hơn lớp 6 mak

a) `123 - 27 + 27 + 13 - 123`

`= (123 - 123) + (27 - 27) + 13`

`= 0 + 0 + 13`

`= 13`

`---`

b) `175 + 25 + 13 + 15 - 175 - 25`

`= (175-175)+(25-25)+25+13`

`=0+0+25+13`

`=28`

`---`

c) \(53\times39+47\times39+53\times21+47\times21\)

\(=\text{[}\left(53+47\right)\times39]+\left[\left(53+47\right)\times21\right]\)

\(=\left(100\times39\right)+\left(100\times21\right)\)

\(=3900+2100\)

`=6000`

`---`

d) \(49\times35+49\times16-49\times61\)

`=` \(49\times\left(35+16-61\right)\)

`=` \(49\times\left(-10\right)\)

`=-490`

a/ 1000 - 47 x 72 - 47 x 28

= 1000 - 47 x (72 + 28)

= 1000 - 47 x 100

= 1000 - 4700

= -3700

b/ 3457 - 27 x 48 - 48 x 73 + 6543

= 3457 - 48 x (27 + 73) + 6543

= (3457 + 6543) - 48 x 100 

= 10000 - 4800

= 5200

k mk nha, mk trả lời đầu tiên đấy

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 + 17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 ) 

A = 72 x 100

A = 7200

C = 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

C = 39 x ( 53 + 47 ) - 21 x ( 53 - 47 )

C = 39 x 100 - 21 x 6

C = 3900 - 126

C = 3774

ko pc tui thua bn 1 lp 

A = 78 x 31 + 78 x 24 + 78 x 17 + 22 x 72

A = 78 x ( 31 + 24 +17 ) + 22 x 72

A = 78 x 72 + 22 x 72

A = 72 x ( 78 + 22 )

A = 72 x 100

A = 7200

dễ tự là

c)(145x99+145)-(143x102-143)

   =   145x(99+1)-143x(101-1)

    =  145x100-143x100

      =     (145-143)x100

       =           2x100

          =          200